memblock, nobootmem: add memblock_virt_alloc_low()

The new memblock_virt APIs are used to replaced old bootmem API.

We need to allocate page below 4G for swiotlb.

That should fix regression on Andrew's system that is using swiotlb.

Signed-off-by: Yinghai Lu <[e-mail]>
Cc: Russell King <[e-mail]>
Cc: Konrad Rzeszutek Wilk <[e-mail]>
Acked-by: Santosh Shilimkar <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: "H. Peter Anvin" <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/arm/kernel/setup.c

···
 	kernel_data.end     = virt_to_phys(_end - 1);
 
 	for_each_memblock(memory, region) {
-		res = memblock_virt_alloc(sizeof(*res), 0);
+		res = memblock_virt_alloc_low(sizeof(*res), 0);
 		res->name  = "System RAM";
 		res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
 		res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;

include/linux/bootmem.h

···
 						    NUMA_NO_NODE);
 }
 
+#ifndef ARCH_LOW_ADDRESS_LIMIT
+#define ARCH_LOW_ADDRESS_LIMIT  0xffffffffUL
+#endif
+
+static inline void * __init memblock_virt_alloc_low(
+					phys_addr_t size, phys_addr_t align)
+{
+	return memblock_virt_alloc_try_nid(size, align,
+						   BOOTMEM_LOW_LIMIT,
+						   ARCH_LOW_ADDRESS_LIMIT,
+						   NUMA_NO_NODE);
+}
+static inline void * __init memblock_virt_alloc_low_nopanic(
+					phys_addr_t size, phys_addr_t align)
+{
+	return memblock_virt_alloc_try_nid_nopanic(size, align,
+						   BOOTMEM_LOW_LIMIT,
+						   ARCH_LOW_ADDRESS_LIMIT,
+						   NUMA_NO_NODE);
+}
+
 static inline void * __init memblock_virt_alloc_from_nopanic(
 		phys_addr_t size, phys_addr_t align, phys_addr_t min_addr)
 {
···
 	if (!align)
 		align = SMP_CACHE_BYTES;
 	return __alloc_bootmem_nopanic(size, align, BOOTMEM_LOW_LIMIT);
+}
+
+static inline void * __init memblock_virt_alloc_low(
+					phys_addr_t size, phys_addr_t align)
+{
+	if (!align)
+		align = SMP_CACHE_BYTES;
+	return __alloc_bootmem_low(size, align, BOOTMEM_LOW_LIMIT);
+}
+
+static inline void * __init memblock_virt_alloc_low_nopanic(
+					phys_addr_t size, phys_addr_t align)
+{
+	if (!align)
+		align = SMP_CACHE_BYTES;
+	return __alloc_bootmem_low_nopanic(size, align, BOOTMEM_LOW_LIMIT);
 }
 
 static inline void * __init memblock_virt_alloc_from_nopanic(

lib/swiotlb.c

···
 	/*
 	 * Get the overflow emergency buffer
 	 */
-	v_overflow_buffer = memblock_virt_alloc_nopanic(
+	v_overflow_buffer = memblock_virt_alloc_low_nopanic(
 						PAGE_ALIGN(io_tlb_overflow),
 						PAGE_SIZE);
 	if (!v_overflow_buffer)
···
 	bytes = io_tlb_nslabs << IO_TLB_SHIFT;
 
 	/* Get IO TLB memory from the low pages */
-	vstart = memblock_virt_alloc_nopanic(PAGE_ALIGN(bytes), PAGE_SIZE);
+	vstart = memblock_virt_alloc_low_nopanic(PAGE_ALIGN(bytes), PAGE_SIZE);
 	if (vstart && !swiotlb_init_with_tbl(vstart, io_tlb_nslabs, verbose))
 		return;